There are many products which, at the time of actual use, consist of ingredients which must be intermixed just prior to use, in view of the fact that after intermixture, the mixture will, after a given time period, become unusable. For example, certain medicinal ingredients, once intermixed, will deteriorate and lose their potency after a given time period. Certain paints and enamels, such as epoxy paints, as well as adhesives, consist of ingredients which, once intermixed, will begin to harden or set up, and become unusable after a given time period. Automobile body filling compound, which at the time of use consists of a paste which may be applied to fill dents or the like in automobile bodies, and which will then harden and can then be shaped, sanded and painted, usually consists of a base material, an acrylic resin and a hardening agent which must be intermixed just prior to usage. This listing of products is by no means complete. The allowable time between intermixture and usage varies widely, ranging from perhaps eighteen hours for paints, down to perhaps one hour for body filling compound, and even much lesser times for medicinal products, each product having different time allowances. Also, certain products, particularly the paints and filling compounds in the products mentioned above, may be desired by the user to be furnished in any one of many different colors.
The above considerations create serious problems in the manufacture, sale and handling of such products. The manufacturer cannot sell the product to the dealer in an intermixed condition, since the time lapse between intermixture and usage would then in many cases amount to weeks or even months. As a result, many products are packaged and sold with the various ingredients in separate containers, which must be opened and the ingredients intermixed by the user just prior to use. This is inconvenient and time-consuming. Also, the intermixture must sometimes be made with very close and accurate control of the proportions of the ingredients, which the user may not have the skill or means to provide. The dealer usually has the facilities to add coloring pigments or agents to paints to supply any desired color, otherwise he would have to stock a prohibitively large number of different colors. However, where as in the present case the main ingredients of the product cannot be intermixed until just prior to use, means must be provided whereby the coloring agents may be added without causing intermixture of the main ingredients.